Take the case of Luton great grandparents Rob and Margaret Holyland, who look and behave like your typical senior citizens.

But scratch just below the surface and hey presto! Their naughty secret is revealed – they’ve featured in a saucy Channel 5 series entitled OAPs Behaving Badly.

“We’ve had tut tuts from our children but the neighbours are unaware of our latest adventure,” Margaret, a 72-year-old sizzler, reveals.

It all started a couple of years ago when the former accounts clerk accompanied her daughter to an audition for Channel 4’s Sex Toy Story – and ended up being selected for a panel advising sex guru Ann Summers about what older women really want.

She told the Luton News at the time that her initial introduction to sex toys was being given a Rampant Rabbit as a joke: “Now I’ve realised they really do help – they’ve certainly spiced up my sex life.”

She added: “After the show went out, someone tried to headhunt me for swingers’ parties – but I told him I wasn’t that kind of girl.”

She was such a hit with programme makers she was subsequently approached to appear in OAPs Behaving Badly, which went out on Channel 5 last Wednesday (March 25).

This time she and her husband Rob were invited to take part in tantric sex lessons with aging pop star Leapy Lea and his pneumatic Danish girlfriend Bettina, self-styled psychic healer Raimondo and geriatric swinging professor Colin.

Margaret says: ”They were the sort of people you’d avoid on holiday – loud, raucous, a real mob. Leapy Lee was really over the top and Raimondo looked like the King of Siam.

“We were the only married couple. There was a workshop with a lady in her 80s called Stella and I thought OMG, what are we doing here, feeling ‘the lurve.’

“We did a dance aimed at loosening up and enticing our partners, which meant wobbling towards them and showing them the bits we thought they might like.

“We also had to lie on the floor and laugh. We weren’t allowed to touch each other and one of the people taking part chose to be blindfolded.”